Hybrid cooling system

ABSTRACT

A hybrid cooling system is disclosed including but not limited to an array of solar cells electrically connected to inverters for producing electricity from the sun; a chiller controller processor in data communication with the inverters and a non-transitory computer readable medium; a chiller in data communication with the chiller controller processor and in thermal communication with inverters in a sealed enclosure, wherein the inverters are cooled by an inverter coolant fluid; an array of solar cells attached to the inverters for producing power from the sun; a free cooler in data communication with the chiller controller processor and in thermal communication with the inverter cooling fluid; and a temperature sensor apparatus in thermal communication with the inverter cooling fluid; a switch for controlling an on off state for the chiller and the cooler, where in the processor for turns the chiller on and the cooler off when the inverter cooling fluid is above a predetermined temperature. A method is disclosed for using the system.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from U.S. Provisional PatentApplication Ser. No. 61/936,390 filed on Feb. 6, 2014 entitled “A HybridCooling System”, which is hereby incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION

Cooling systems for electrical power generation are part of the solutionto new power generation methodologies.

FIELD OF THE INVENTION

The present invention relates to a hybrid cooling system for anelectrical inverter.

SUMMARY OF THE INVENTION

In one particular embodiment, the present invention provides a hybridcooling system for an electrical inverter. The present inventionprovides the hybrid cooling system that is a combination of a radiatorand a chiller. The radiator cools water that is supplied to theelectrical inverter during normal temperature conditions and the chillercools the water only when the radiator is not able to cool the watertolerate the temperature. The chiller is used only during the few hoursof the day during a portion of the year, i.e., midday during the summermonths and rest of the time radiator is used thereby reducing the powerconsumption.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic representation of a particular embodiment ofthe invention comprising a hybrid cooling system;

FIG. 2 depicts a schematic representation of another particularembodiment of the invention comprising a hybrid cooling system; and

FIG. 3 depicts a schematic representation of another particularembodiment of the invention comprising a hybrid cooling system;

FIG. 4 depicts a schematic representation of another particularembodiment of the invention comprising a hybrid cooling system;

FIG. 5 depicts a schematic representation of another particularembodiment of the invention comprising a hybrid cooling system;

FIG. 6A-6D depict an illustrative embodiment the invention showing of alist of inputs and outputs to the chiller controller processor 150 isshown;

FIG. 7 depicts a fluid controller scheme for a particular illustrativeembodiment of the invention is depicted;

FIGS. 8-11 depict a particular embodiment of the invention of a manifoldassembly scheme is depicted;

FIG. 12 depicts a water cooling diagram for a drive section in aparticular embodiment of the invention is depicted; and

FIG. 13 depicts a control loop for a particular illustrative embodimentof the invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In a particular embodiment, with a 23° F. minimum ambient, a 10-20%solution of inhibited propylene glycol (industrial grade) is provided asa cooling solution for electrical inverters. In a particular embodimentof the invention, DOWFROST™ or an equivalent is sufficient. In anotherembodiment of the invention, an internal heat exchanger (HX) isprovided. In one embodiment, a stainless HX is provided. The stainlessHX enables a designer to not have to worry about copper in theevaporator and brass, bronze etc. components in the cooling system. Inanother embodiment, a temperature control loop is provided with a valveand sensor, which allows the chiller to operate at a somewhat lowertemperature say 70° F. (without affecting actual temp to the drive).

In another embodiment, a controller provides controls signals for ahybrid cooling system. In a particular embodiment, the controller isMODBUS capable controller processor. In another particular embodiment,the controller processor is Ethernet IP capable with a converter.Discrete IO (analog and digital) is also provided. Air inlets areprovided as a filtering mechanism on the condenser air inlets forchallenging installation environments. A filter test and cleaning systemare provided. The inventor has determined that, no matter what kind offilter you put on a particular embodiment of the chiller, a chiller useslots of air flow so if the environment is prone to plugging the filter.In another particular embodiment, a course of action is provided toclean the filter periodically or when a filter alarm issues.

In another particular embodiment, a multi-million dollar installation ina remote location is dependent on a chiller, thus redundant chillers areprovided. Chillers move lots of air so the chiller processor determinesthe state of the filters with respect to plugging and/or cleaningthereof. In general, the chiller should be fairly okay with being turnedon and off as the load requires. The chiller processor modulate thechiller's capacity in order to continue running at partial loads for thewater cooled solar inverter. If the water cooled solar inverter iscycling to a no-load status, then the chiller compressor would cycle.

In a particular embodiment, a water to air radiator is provided to coola water-cooled solar inverter about 90% of the time because water to airradiation is an efficient way to remove the heat from the cooling waterthat is added to the water while the solar inverter is producing power(also referred to herein as “the process”). The maximum cooling watertemperature that the inverter can reasonably tolerate and operate is 40Degrees C (104 Degrees F) and the prime location for these SolarInverter installations is in the desert where ambient air temperaturessoar. Since the operation is in the desert, the solar inverter is ratedfor operation up to 50 Degrees C (122 Degrees F). If the outside ambienttemperature reaches 50 Degrees C, the radiator may very well turn into awater heater, instead of a water cooler (relative to the 40 degrees Cthat an illustrative embodiment of the cooling system can comfortablytolerate). Therefore, in a particular embodiment of the invention, anactive water chiller is provided to cool the water during these highambient temperatures. The problem is that active water chillers such asrefrigeration circuits are not energy efficient, thus unless usedjudiciously and sparingly, use too much energy, thereby reducing theeffectivity of the process that is there to produce energy. Also, wedon't want to simply shut down the process during these high ambienttemperature conditions because these will typically occur when the sunis the brightest and hottest and the process can produce the most powerfrom the farm of solar panels connected to the energy inverters. Thus,using an embodiment of the present invention provides a hybrid coolingsystem, where the hybrid cooling system uses the active chiller(refrigeration circuit discussed below) during the few hours of the dayduring the year (midday during the summer months) when the heat soarsand uses the simple water to air heat exchanging radiator the rest ofthe time.

Turning now to FIG. 1, an illustrative embodiment 100 of the presentinvention is depicted schematically in FIG. 1. The purpose of thissystem is to provide cooling to some liquid cooled solar inverter drives(the process) and associated electrical components such as chokes. In aparticular embodiment, the process coolant fluid is a propylene glycolsolution and the desire is to maintain a supply temperature of 35° C.(95° F.)±2° C. in an energy efficient manner during ambient conditionsthat range from 23° F. to 122° F. The hybrid cooling system concept fora particular illustrative embodiment of the invention is illustrated inFIG. 1. In a particular embodiment as illustrated in FIG. 1, the hybridsolar inverter cooling system includes but is not limited to an aircooled chiller (refrigeration circuit) and a free-cooler 129 (water toair radiator). The free cooler (water-to-air radiator) is used duringthe majority of the year to reject process heat generated by the liquidcooled solar inverters directly to the ambient air and the chiller isdesigned to reject heat generated by the process through a refrigerationcircuit to the ambient air when the ambient temperature is above atemperature that will allow the desired coolant supply temp to bemaintained with the cooler. The hybrid cooling system provides a chillerprocessor that runs both the chiller and the cooler and determine wheneach should be running The hybrid cooling system provides for chillerprocessor communications using a communications protocol (MODBUS) andwith discrete and analog signals.

An illustrative embodiment of the hybrid chilled coolant circuit isdepicted schematically in FIG. 1. An illustrative embodiment of the freecooler loop is schematically depicted in FIG. 1. As shown in FIG. 1, arefrigeration loop 140 and a coolant loop 141 are provided in anillustrative embodiment. Warm coolant (water and glycol mixture) returnsfrom the process and goes into the reservoir tank (T-1) 102. The tank isconstructed of stainless steel and has a closed top (vented toatmosphere) to limit ingress of contaminants. The coolant is then pumpedthrough a strainer to remove large-scale contaminants that might plugthe evaporator and the travels on to a brazed plate evaporator (HE-3)104 where it is cooled. A brazed plate evaporator is provided that hasalternating plates of copper and stainless steel that are brazed in ahigh temperature furnace. The evaporator provides four connections, 2for water and 2 for refrigerant. The water and refrigerant pass on toopposite sides of the plates to exchange heat.

A pump discharge pressure transducer (PT003) 106 provides feedback ondischarge pressure which can be used in comparison with a pump curve forthe system pump P-1, to estimate flow. A flow switch (FSL001) 108ensures that sufficient flow is being provided to the evaporator. Afterthe evaporator, a temperature sensor (TE001) 110 is provided that isused to monitor and control the temperature in the desired range bycycling the compressors (C-1 112, C-2 114) and actuating the modulatinghot gas bypass valve (FCV-001) 116 to control the temperature. (See therefrigeration circuit discuss below for more details.) The cooledcoolant fluid flows either back into the reservoir or alternately intothe process pump (P-2) suction as dictated by the position of the 3-wayprocess tempering valve (FCV003) 118. If the chiller is running, thechiller processor controller 150 attached and data communication(exchanging data back and forth with) with non-transitory computerreadable medium 152, executes a computer program stored in the computerreadable medium to determine that cooling is required to the coolantprocess circuit, the valve 3-way process tempering valve is actuated bythe chiller processor controller to divert a portion of returning waterback to the reservoir, T-1, thereby bringing cooler water into theprocess pump P-2 120.

The process water circuit maintains the temperature of the coolant fluidsupplied to the drives at 35° C. (95° F.)±2° C. At temperatures up to90° F., the free cooler can accomplish this. Above 90° F., however, thechiller processor at least partially switches off the free coolercircuit and at least partially switches on the chiller circuit to supplycooled water to achieve the cooling of the fluid supply to the drives.The process pump (P-2) 120 pushes the process coolant, glycol solutionpast the process temperature supply sensor (TE004) 122, pressuretransducer (PT005) 124, flow switch (FSL002) 126, full flow 100 micronfilter assembly and through a heater (HTR001) 125 before going out tothe process to cool the inverters and associated electronics. The valuefrom the temperature sensor is used by the chiller processor to actuatethe 3-way process tempering valve (FCV003) 118 when the chiller is on.The chiller processor controller controls and utilized this same valueto control the cooler fans (F-3 128 and F-4 130) and the position of the3-way free-cooling modulating valve (FCV004) 132 when the free-cooler(HE-4) 129 is operating. The chiller processor uses the pressuretransducer for informational purposes and the flow switch to insure thata minimum process flow is being met. The heater provides the ability toraise the loop temperature (in case of lower temperature startup) andthe full flow filters provide protection against contaminants going tothe drives.

The fluid coolant returns from cooling the process inverters andassociated electronics, where the chiller processor controller sense thereturn temperature (TE002) 131 which is also used in control of the freecooling modulating valve (FCV004) 132. The free cooling modulating valve132 is manipulated by the chiller processor controller 150 to determinehow much flow goes to the free cooler 129 and how much bypasses thecooler. In chiller only mode, the free cooling modulating valvecompletely diverts the water back to the return line bypassing the freecooler 129. In free-cooling mode, the free cooling modulating valvemodulates so as much water as is needed to maintain the processtemperature flows to the cooler. In an illustrative embodiment, the freecooler 129 is a large water-to-air heat exchanger with copper coils andaluminum fins. The chiller processor controls circulates the coolantfluid through the free cooler copper coils and draws air across the freecooler coils to remove the heat from the fluid. In a particularembodiment, the free cooler is selected to provide a cooling capacity tocool 64 gallons per minute (GPM) (240 liters per minute (LPM)) flow to95° F. with 90° F. ambient air while removing 40 kW of heat.

In a particular embodiment, in a free cooling mode, the chillerprocessor positions the 3-way tempering valve (FCV003) 118 to fullydivert the returning water from the process cooling, back to the processpump suction (P-2) 120, which helps to keep the reservoir of water intank T-1 at a lower temperature, facilitating a chiller startup processduring which the tank will pull down prior to switching over from usingfree cooler for cooling to using the chiller for cooling the processcoolant.

Turning now to FIG. 2, the chiller cooling loop is schematicallydepicted. In an illustrative embodiment a refrigeration circuit (alsoreferred to herein as the refrigeration loop) 140 is provided. Therefrigeration circuit utilizes R410A refrigerant which is recognized asone of the best performing refrigerants for the process based onefficiency and GWP (global warming potential). R410A is the dominantrefrigerant globally and particularly in the western hemisphere.All-aluminum micro-channel condensers are provided in an illustrativeembodiment. The refrigeration loop cycle starts with low pressure, lowtemperature gas going into the two compressors (C-1, C-2) where the gasis compressed to a high pressure, high temperature gas. The chillercontroller processor uses pressure transducer (PT001) 202 to sense andmonitor the refrigerant suction pressure as a safety to monitor againstlow pressure. The chiller controller processor uses another transducer(PT002) 204 to sense and monitor discharge pressure and protect againstover-pressure. A mechanical high pressure switch (PSH001) 206 isprovided as pressure relief and acts as a redundant safety and a reliefvalve (PSV001) 208 is provided to act as a final safety.

In an illustrative embodiment, the chiller processor controller directsthe high pressure, temperature gas either to micro-channel condensersHE-1A, 1B 210 and HE-2A, 2B 212 where the gas passes through smallmicro-channels to which aluminum fins are attached or directly back tothe inlet of the evaporator (HE-3) 104 through the modulating hot gasbypass valve (FCV001) 218 bypassing the condensers (discussed furtherbelow). For the gas directed into the condensers HE-1A, 1B 210 andHE-2A, 2B 212, the two fans, F-1 214 and F-2 216 draw air through thecondenser coils which results in heat being transferred from therefrigerant to the ambient air surrounding the refrigeration circuit. Asthe refrigerant cools, it condenses forming a liquid which passes out ofthe condensers into a copper refrigerant line before proceeding to thefilter/drier which removes any contaminants or moisture from therefrigerant. The refrigeration circuit fans speed is controlled by thechiller controller processor via an ABB VFD to maintain condensingpressure particularly in lower ambient temperature conditions. Thecondenser selection is selected to provide the total heat exchangerequired by the process up to 122° F. ambient while also maintainingproper operating conditions down to the minimum temperature of 23° F.

In an illustrative embodiment, the liquid refrigerant proceeds past theliquid line solenoid valve (FCV002) 220 which is provided to preventrefrigerant migration when the chiller is turned off, and is meteredinto the evaporator (HE-3) 104 by the thermostatic expansion valve(FCV005) 222. This valve is designed to meter liquid refrigerant intothe evaporator at a rate designed to ensure that all the liquidrefrigerant evaporates prior to leaving the evaporator. The liquidrefrigerant mixes with any hot gas that has been directed around thecondenser and proceeds into the evaporator where it changes state to alow temperature gas thereby absorbing the heat from the water throughthe walls of the evaporator. The hot gas bypass valve (FCV001) 218 isprovided to maintain load and temperature control without cycling thecompressors off during lower loads and fans which will maintain bettercontrol than a cycling system that cycles on and off with less wear andtear on those components. In cases where the load is below 50%, thechiller controller processor cycles off one of the two compressors thusreducing total energy usage. The two compressors automatically lead/lagto keep even running time. The low pressure gas exits the evaporator tobegin the refrigeration cycle again.

The chiller processor controller provides control of switchover betweenchiller and free cooler predicated on the ambient temperature sensor(TE0003) 220 and actual process temperatures. The chiller processorperforms switchover to the chiller will commences when the ambientexceeds 90° F. and the process temperature exceeds 95° F. The chillerprocessor performs switchover back to the cooler would occur when theambient drops below 88° F.

The chiller controller processor on the chiller collects significantamounts of data including fluid temperatures, fluid pressures,refrigerant pressures, motor status and the ambient temperature of theair surrounding the hybrid cooling system. The chiller controllerprocessor then uses this data in a variety of routines. The initialchillers include MODBUS RTU via RS485. The chiller controller processormonitors active alarms as they occur. MODBUS is also provided via aninternet protocol Ethernet. In an illustrative embodiment, the chillerprocessor converts the MODBUS to PROFIBUS. In another illustrativeembodiment, individual discrete/analog signals are provided.

Turning now to FIG. 3, an illustrative embodiment of the invention 300is depicted in schematic form. As shown in FIG. 3 an air to water heatexchanger 320 runs continuously to cool the water at ambient airtemperature. In a particular illustrative embodiment, the air to waterheat exchanger 320 is provided with two lines 324 and 326 for the waterto air heat exchanger and two lines 321 and 323 for the chiller 319. Inanother illustrative embodiment, a separate heat exchanger for thechiller is provided. As shown in FIG. 3, cooled water is used to cooldown the drive 316 and the enclosure 310 via a small water to air heatexchanger 312. In a particular embodiment, the small heat exchanger 312is provided and controlled by the chiller processor controller tomaintain the air 330 inside the sealed enclosure and the water flowingthrough heat exchanger 312 to avoid condensation inside the sealedenclosure. Condensation can drip on the drive 316, choke 314 andassociated electronics 315 inside the sealed enclosure 310. A pair ofchillers 318 and 319 are provided in a particular illustrativeembodiment of the invention. The chiller controller process cycles onthe chillers when the heat exchanger 320 is insufficient to cool thedrive 316 to below maximum operating temperature. In a particularembodiment, a water leak sensor 311 is provided inside the sealedenclosure 310. In a particular embodiment, the water leak sensor isinsulated wire that provides a short circuit when exposed to water. Thewater penetrates a water penetrable insulation on the wire and providesa short circuit. The short circuit is sensed by the chiller controllerprocessor 150. The chiller controller processor can then shut down thedrive 316, choke 314 and associated electronics 315 when water isdetected inside the sealed enclosure to prevent short circuiting of thedriver, choke and associated electronics.

Turning now to FIG. 4, in a particular illustrative embodiment 400 of asealed enclosure 403 is depicted. As shown in FIG. 4, each sealedenclosure contains a chiller controller processor 150, a non-transitorycomputer readable medium 152. Each enclosure 403 further contains threeinverters 402, 404 and 406 and three chokes 401, 403 and 405. Eachinverter and choke is temperature controlled by coolant flowingselectively through the chiller refrigeration circuit and the freecooler. A temperature sensor “t” 411 is provided to sense thetemperature on individually on each inverter/choke combination 1, 2, and3 and sealed enclosure temperature sensor 412 to sense the cabinettemperature. A humidity sensor 414 and dew point sensor 416 are providedto determine the humidity and dew point inside the sealed enclosure 403.An air conditioner 420 is provided in the sealed enclosure to heat orcool the air inside of the sealed enclosure. A water detector 410 isprovided to detect water inside of the sealed enclosure. Three inverterfans 414, 416 and 420 are provided to help cool the inventors and chokesinside the sealed enclosure. The processor monitors the sealed enclosuretemperature, the humidity level and the dew point to determine if thereis risk of the coolant 422 flowing into the sealed chamber and thecoolant flowing out of the sealed enclosure reach a temperature that maycause condensation of water in the air inside the sealed enclosure. Ifthe processor determines that the temperature air is too cool and mayallow condensation, the air is warmed by the AC 420. If the processordetermines that the temperature air is too warm and may heat up thecabinet and inverters, the air is cooled by the AC 420. Solar panels 505are electrically connected to the inverters in groups 500. The invertersare provided with a current limiting control so that the inverters canbe de-rated from 100% capacity when the processor determines that it isdesirable to do so.

Turning now to FIG. 5, in another particular embodiment, the enclosure400 one of many enclosures connected to a solar panel farm 502 and indata communication (exchanging data back and forth) with a mastercontroller 542. The master controller is connected to a cloud computingapplication, such as the internet which is in data communication with auser interface 512. Using the user interface and the master controller auser 514 can control the many enclosure to electronically de-rateindividual inverters by sending current limiting commands to eachcontroller for each inverter in a particular sealed enclosure.

In another particular embodiment the master controller includes aprocessor 150 and non-transitory memory 152. The processor memory 152includes but is not limited to a neural network containing historicaldata about the energy efficiency of the enclosures and the solar panelfarm. In another embodiment each enclosure processor includes but is notlimited to a neural network for containing historical data about theenergy efficiency of the enclosures and the portion 500 of the solarpanel farm to which it is connected.

The neural network monitors and senses all inputs and outputs, allelectrical components and sensors in each enclosure, water and coolantflow pressures and temperatures for the free cooler and chiller andmakes decisions as to controlling the components to achieve a desiredefficiency in net energy production based on these inputs and outputs.

Turning now to FIG. 6A-6D, an illustrative embodiment the inventionshowing of a list of inputs and outputs to the chiller controllerprocessor 150 is shown. Turning now to FIG. 7, a fluid controller schemefor a particular illustrative embodiment of the invention is depicted.Turing now to FIG. 8-11, a particular embodiment of the invention of amanifold assembly scheme is depicted. Turning now to FIG. 12, a watercooling diagram for a drive section in a particular embodiment of theinvention is depicted. In a particular illustrative embodiment, theprocessor 150 is in data communication with all of the electricalcomponents inside of the sealed enclosure.

FIG. 13 depicts a control loop 1300 for a particular illustrativeembodiment of the invention. As shown in FIG. 13, the chiller controllerprocessor reads 1302 inputs from various sensors inside the sealedenclosure, the chiller, the free cooler 1304 and outside temperature todetermine how to set the system for efficiently producing electricity.The chiller processor controls reads energy production reductionrequests 1306. The chiller controller senses the operation of the systemand ambient temperature and adjusts the electrical components inside thesealed enclosure along with the chiller and free cooler to reduceelectrical energy consumption needed to run the fans, chiller andincrease net electrical energy produced 1308.

In particular embodiment, the chiller controller processor reads theshutdown voltage from the day before, that is, the voltage when the sungoes down and sets the startup voltage for the system at the shutdownvoltage plus 10%. The shutdown voltage is the voltage at which thesystem quits producing more energy that it uses to run the chiller,inverters, free cooler fans and entire system used to produce electricalenergy. The chiller controller process then reads the voltage producedby the solar cell array and turns the system on when the voltageproduced by the solar cell array exceeds the startup voltage. In aparticular embodiment, the chiller controller processor reads theambient air temperature, the inverter temperature, the coolanttemperature going into the sealed enclosure and the temperature of thecoolant coming out of the sealed enclosure, the temperature of the airinside the sealed enclosure, the humidity inside the sealed enclosureand the dew point inside the sealed enclosure and sets the system toproduces electricity with a reduced electrical energy used and anincreased net electrical energy produced.

In a particular embodiment the chiller processor controller modulateshot gases from the chiller condenser to heat coolant when the coolantentering the sealed enclosure can cause condensation of water from theair inside the sealed enclosure, thereby reducing the chance ofelectrical short circuit of the electrical components inside the sealedenclosure. In a particular embodiment, the chiller controller processorstages the two chiller compressors based on the heat load place on thechiller. If the load required to keep the process running below maximumoperating temperature is less than the capacity for the first one of thecompressors, only the first one of the chiller compressors is turned onand used. Once the heat load increases to a particular percentage of thefirst chiller compressor's capacity the second one of the two chillercompressor is turned on and used. Once both compressor are turned on thechiller controller processor shares the load between the two chillercompressors. In another particular embodiment the neural network in thechiller controller processor sets the load on the two compressors toreduce the amount of energy used to produce energy without uses excesselectrical energy to produce energy from the solar array for the currentlevel of electrical energy produced by the solar array feeding into thesealed enclosure at the currently measure ambient temperature, coolantin and out temperature and energy production desired from the solararray while avoiding cycling one or both of the compressors off and ondue to fluctuations in the amount of energy being produced by the solarcell array 500. The compressor fan speeds and the compressors arecontrolled for reduced energy usage for current level of electricalenergy produced by the solar array feeding into the sealed enclosure atthe currently measure ambient temperature, coolant in and outtemperature and energy production desired from the solar array whileavoiding cycling one or both of the compressors off and on due tofluctuations in the amount of energy being produced by the solar cellarray 500.

The chiller controller processor uses the air conditioner in the sealedenclosure is used to heat or cool the air inside of the sealed enclosureto avoid condensation of water from the air inside of the sealedenclosure for a given temperature, humidity and dew point. The chillercontroller processor monitors the temperature inside of the sealedenclosure, the ambient temperature, the load for the inverters from thevoltage produced by the solar cell array 500, the temperature on theinverters from sensor “t” 411, and uses the AC inside the sealedenclosure to cool the air in the sealed enclosure to prevent inverteroverheating when the air is too warm and to warm the air inside thesealed enclosure to prevent condensation when the air is too cool. Inanother particular embodiment the neural network controls the AC insidethe sealed enclosure based on historical data for the sealed enclosureto achieve an efficient net energy production from the system.

In a particular embodiment the chiller controller processor controls thefan speeds for the two chiller fans for the free cooler for an efficientnet energy production from the system. In a particular embodiment, avariable speed fans are provided on the compressors and the chillercontroller processor varies the speed of the fans on the compressor tocontrol the temperature of the compressor gas entering and leaving thecompressor to achieve a consistent discharge pressure from thecompressor. In another embodiment the input and output pressure for thecompressor is monitored by the chiller controller processor to detectproblems such as a clogged filter or a leak when a difference between apressure of gas coming into the compressor and a pressure of gas leavingthe compressor exceed a predetermined alarm threshold. In anotherparticular embodiment, the compressor fan speeds are controlled by theneural network based on the incoming and discharge pressure for thecompressor.

In another particular embodiment, the chiller controller processorsenses the process temperature supply at sensor TE4, the ambienttemperature at TE3 and adjusts the FCB4 free cooler mod valve to adjustthe return temperature of coolant to the process to achieve efficientenergy production by controlling the free cooler fan speeds.

When the ambient temperature is too high, that is, the temperature ofthe inverters is above the maximum operating temperature, the chillercontroller processor sends a currently limiting command to the invertersto de-rate the inverters to a lower output to allow the inverters tokeep operating at a lower capacity. In a particular embodiment thecurrent limiting commands are sent to the inverters in the sealedenclosure from the master controller or the user interface from a remotelocation.

In another particular embodiment, an energy reduction request isproduced by a utility company to reduce excess power produced by thesystem and supplied to the grid by the system. In particular embodiment,the chiller controller processor request a 20% reduction in powerproduced. The chiller controller processor sends a currently limitingcommand to the inverters and adjusts the chiller and free cooler toproduce net energy efficiently at the reduced power production level. Inanother embodiment, the neural network adjusts the chiller and freecooler to produce net energy efficiently at the reduced power productionlevel based on historical data for the system.

In a particular embodiment, the 3 inverters are staged for efficient netenergy production so that only one inverters is turned on to until thevoltage produced from the solar cell array approaches the capacity ofthe one inverter is used and then a second inverter is turned on. Oncethe second inverter is turned on and the load from the solar cell arrayis shared between the first and second inverters at a rate historicalshown to produce a substantially maximized net energy production for thegiven voltage produced by the solar cell array. When the two invertercapacity is used by the solar cell array a third solar cell array isturned on and the load is shared between the three inverters toefficiently produce a net energy production with substantially the leastamount of power used to produce the energy.

In a particular embodiment, the solar cells are rated to produce moreenergy than the inverter can handle, so that at peak hours of the day,when the solar cells are producing the most energy, the chillerprocessor controller limits the amount of power produced by theinverters so that one inverter may run at 100% and another one run at40%. Limiting the production of the inverters in performed to avoidturning the inverters on and off and using more energy than it wouldtake to limit the inverters to produce the energy. In a particularembodiment a neural network uses historical data, learned frommonitoring the system inputs and net energy produced. Thus, in aparticular embodiment, when the ambient air temperature is too hot torun the inverters at full capacity, the chiller controller processorwill de-rate the inverters to reduce the amount of energy produce, forexample by 25%, to allow the inverters to continue running at atemperature higher than their full maximum output level operatingtemperature. In another embodiment, the neural network uses historicaldata learned from the system to adjust the inverters, condensers andfree cooler to use the least amount of energy to produce the most netenergy for a given combination of ambient temperature and desired netenergy production.

In a particular embodiment, the chiller processor will de-rate theinverters and run the inverters at a higher temperature so that the onthe free cooler is used and the chiller is not needed to produce a givenamount of net energy production for a given ambient temperature andcoolant temperature for a given voltage supplied by the solar cellarray. In another embodiment, the variable speed fan blades pitch isaltered by the chiller controller processor to control the amount of andspeed of cooling air provided by the compressor and cooler fans. Inanother embodiment, flow of the process coolant is regulated by thechiller processor for net energy production efficiency.

In another embodiment, historical and current actual cloud over andmeteorological data are used by the neural network to control the netenergy production by adjusting the system based on past learned settingsobserved by the neural network. The meteorological data includes but isnot limited to current cloud cover, rain, wind speed and ambienthumidity.

In a particular embodiment, the hybrid cooling system includes but isnot limited to the following Major Components: Copeland scrollcompressors, Belimo 3-way valves, Krack/Hussman free cooler with coppertubes, aluminum fins and galvanized frame, Heatcraft all aluminumcondenser coils, ABB main disconnect, Allen-Bradley 190E Series, OAO fanmotors suitable for outdoor duty with ABB VFD for control, Multi-wingfan with aluminum fan hub and glass reinforced polypropylene blades,Ebara, Scot or equivalent TEFC pumps, SWEP or equivalentstainless/copper brazed plate chilled water evaporator, Carelprogrammable controls, Stainless steel reservoir (closed, vented toatmosphere), Keystone plastic bowl-style full flow bag filters, Copperrefrigerant piping, Water circuit of brass, bronze, plastic, PVC andhose, Sporlan or equivalent refrigeration components, Galvanized modularframe with powder coated panels and NEMA-4 Control/Power Enclosures anda Chiller Processor Controller.

In another particular embodiment, the following are provided: a Watercooled variable speed drive. The maximum cooling inlet water temperatureis 37° C., for condensation concerns, thus the chiller processorsubstantially stabilizes the cooling water temperature at 35° C., +/−2°C. max. If the cooling water temperature is too cold, it could causecondensation on the pipes causing short-circuits if the condensed wateron the pipes drips into electronic and electrical circuitry. In aparticular embodiment, the drive maintains maximum efficiency up toambient temperatures of 50° C. at the site. A particular illustrativeembodiment of the invention provides a simple air/water radiator, with aforced air fan blowing air through the radiator to water cool the drive.It's expected that the air/water radiator cooling will be efficient formost of the year. For approximately 2 months out of the year, theprocess site location will experience very hot days. On these days, theair to water radiator would act as a heater, not a cooler. So we need toshut this system off, and during these times use a chiller system tocool the drive. The water-to-air fluid cooler will be used when ambienttemperatures are 33° C. or below, to provide a large enough deltatemperature to keep the drive temperature below 41° C. maximum processoperating temperature. The inverter lineup will packaged in a NEMA 4rated enclosure outdoors, and the chiller/fluid cooler will be packagedby EPD in a NEMA 3 enclosure, isolated from the electrical components.

In a particular illustrative embodiment, the Liquid Cooled ComponentsSpecifications as provided are Qty (3) 415 KW Drives, Qty (9) Reactors.System Heat Losses are Losses to liquid: Per Drive: 9.2 kW, 3 drives*9.2kW=27.6 kW, Per Reactor: 480 Watts, 9*480 W=4.32 kW. Water-to-Air ACunits, 5 kW, Total: 37.92 kW losses to liquid—40 kW total. Losses to airare Per Drive: 600 W, 3 drives*600 W=1.8 kW, Per Reactor: 110 Watts, 9reactors*110 W=990 Watts. Total: 2.79 kW losses to air—3 kW total. Flowrate specifications are Per Drive: 35 l/minute (minimum flow per drive:20 l/min), 3*35 l=105 l/min, Per filter: 10 l/minute, 9*10 l=90 l/min,Total Flow rate=195 l/min Estimated flow for AC units=25 l/min, 240l/min total flow provided. In a particular embodiment a Pressure Drop:Across each drive is 1.5 bar @ 35 l/min, Across each reactor: 0.4 bar @8 l/min. In a particular embodiment, a Glycol/water solution isprovided, 20% solution of inhibited propylene glycol mixture, i.e.,Dowfrost (or equivalent). In a particular embodiment, the Water Circuitis made of a Standard non-ferrous components (plastic, stainless,copper, brass and bronze). For electrochemical corrosion an inhibitorsuch as Ferrolix 332/Henkel, or VpCl-649 needs to be added to thecooling medium prior to use.

In a particular embodiment, the Environmental Conditions are for anInland location with an elevation of ˜1,300 M (4,265 ft.). A minimumexpected ambient temp—5° C. or 23° F. with a maximum expected ambienttemp of 50° C. or 122° F.

In a particular embodiment, the hybrid cooling system is provided having40 KW with MODBUS control protocol and using two compressors in lieu ofone. In a particular embodiment, the Heat load is 40 kW (11.4 tons),Flow to be approximately 64 GPM (240 LPM), Pressure to be approximately40 PSI (maximum pressure no more than 6 bar), 100 micron side-streamfilter on recirculation circuit. In a particular embodiment aninstallation location is to be outdoors in Mexico at 4,300 ft.elevation. The chiller design is to be air cooled. The ambienttemperature range is 23° F.-122° F. The chiller is to be constructedwith nonferrous water side components. The design coolant supply setpoint is 35° C. (95° F.). The coolant to be 20% propylene glycolsolution. The water circuit construction to be stainless, copper, brass,bronze, plastic, PVC. The install location is non-hazardous and does nothave elevated levels of sulphur. The chiller frame is standardgalvanized and cabinetry is powder coated. The free cooler cabinet isprimarily galvanized, with conduit and wiring to be suitable for outdoorduty, power is 460V/3/60 and the system to include free cooling (directair to water cooler to function when ambient temperatures are at 90° F.or below).

In an illustrative embodiment, the refrigeration circuit runs at amaximum of 80° F. water temperature. Since the project requirement isfor 95° F., a tempering loop is provided inside of the chillerconsisting of a 2nd pump and 3-way control valve to temper the processwater to 95° F. The free cooler will operate to provide cooling for thesystem as long as the ambient temperature is 90° F. or below. Above 90°,the chiller will operate to maintain the process temperature no higherthan 95° F. (35° C.). The fluid will be diverted to the cooler by a3-way valve contained in the chiller.

Communications between the chiller and chiller controller processor arein the form of discrete and analog signals (total number of signals tobe determined) or MODBUS. Future development of PROFIBUS communicationprotocol expected. The chiller and fluid cooler have separate main powerdrops. A Model AC2A10-ODHTFC Air Cooled Chiller package rated for 11.4tons of cooling capacity with 122° F. ambient air temperature. IncludesMODBUS and two compressors. A Model EC-11 Water-Air Fluid Cooler ratedfor 11.4 tons of cooling capacity with 90° F. ambient air temperature isprovided. The package has a power panel requiring a power drop withcontrol wiring run from the chiller. The cooler integrates into thesystem as suggested in FIG. 1 and FIG. 2.

Efficient microchannel condensers provide full rated capacity with highambient conditions. These chillers are provided with microchannelcondensers. Microchannel condensers exhibit numerous advantages over thetraditional tube and fin condensers. Microchannel condensers are moreefficient and allow for less refrigerant charge to be used which makesMicrochannel condensers the “green”, energy efficient solution. Thedesign is inherently more durable and efficient since the fins have ametallurgical bond to the tubes and they are all aluminum therebyeliminating the potential corrosion concerns associated with coppertubes.

In a particular embodiment, HFC-410A (Puron) refrigerant is providedwhich meets Montreal Protocol requirements. HFC-410A is the refrigerantof choice to replace HCFC-22, which was phased out for new equipment atthe end of 2009. It is the most common refrigerant in the country, whichmakes it easier to support with local service technicians. HFC-410A ismore environmentally friendly and more energy efficient than HCFC-22 orHFC-407c. HFC-410A is an azeotropic blend, so it can be rechargedwithout the challenges associated with the zeotrpoic blends such asHFC-407c.

In a particular embodiment, the chiller controller processor is aprogrammable microprocessor provided for high reliability and tighttemperature control. The programmable microprocessor controller providesexpandable functionality and tight temperature control. The chillercontroller processor has UL, CSA, and CE certifications, so it can bemarketed everywhere and meet the local codes. This microprocessoraccepts thermistor temperature sensors, so it can provide accuratetemperature control based upon accurate inputs. This will greatly reducethe chance of freeze-ups that can be caused by out-of-tolerancetemperature sensing or erratic temperature control.

In a particular embodiment, as shown in FIG. 2, a Remote MicroprocessorDisplay provides convenient monitoring of chiller. As standard, themicroprocessor display is provided with a magnetic backing and a 20 footcable (longer cables available). This allows the operator to monitor thechiller operation from a convenient location. This is a particularlyimportant feature if the chiller is going to be located up on amezzanine above the laser system.

In a particular embodiment, chiller controller controls modulating ofhot gas bypass and staging of compressors which provides temperature andcapacity control with low loads. Based upon the number of machinesoperating and several other factors, the heat load placed on the chillercan vary greatly from full load to almost no load. It is a challenge tomaintain temperature across this wide range. The combination of themodulating hot gas bypass valve along with compressor unloading enablesthe chiller processor to provide tight control down to no load withoutcycling the compressor. Unloading of a compressor at lower loads alsosaves significant energy.

In a particular embodiment the chiller processor provides for variablefrequency drive (VFD) Controlled Fans provide stable head pressure,which results in tighter temperature control and greater reliability.Varying the speed of the condenser fan motors provides for asubstantially more consistent refrigerant discharge pressure for thecompressors. Varying the speed of the condenser fan motors results inbetter temperature control even with variable process loads and ambientconditions. The VFD control extends the life expectancy for the fanmotors, and the more consistent refrigerant discharge pressure can alsoextend the life expectancy for the compressors. Running the fans at aslower speed also reduces the energy consumption.

In a particular illustrative embodiment, the chiller processor providesenhanced diagnostic capability facilitates field troubleshooting andreduces downtime as shown in FIG. 3. Process Water Pressure, RefrigerantSuction Pressure, and Refrigerant Discharge Pressure are provided ondigital displays on the chiller processor microprocessor. These digitaldisplays make start-ups go smoother since the technicians will have moreinformation to work with. It will also make field troubleshootingeasier, which will significantly reduce downtime when an issue doesarise.

In a particular illustrative embodiment, the Chiller is designed to meetNFPA-70 (NEC Code) and NFPA-79 with UL/C-UL certified panel. Manycustomers are now demanding that equipment meets these codes. In certainareas of the country, these codes are required by law.

In another particular embodiment, a Chiller Maintenance Required Alarmprovides early warning indicating that preventive maintenance on thehybrid cooling system should be scheduled. The chiller processor controlsystem on the chiller is designed to provide an advance warning wheneverpossible that the chiller will be having a potential problem in the nearfuture. It does this by monitoring several of the critical parametersand sending out a warning signal if one of these parameters straysoutside of the normal operating range. This allows the operator toschedule the maintenance when it is more convenient and possibly avert amore expensive failure mode.

In a particular embodiment, a Scroll compressor is provided for improvedreliability and energy efficiency along with generously sizedmicrochannel condenser for industrial environments. Also provided are atop discharge fan and cleanable condenser air inlet filter, Brazed plateevaporator provides higher efficiencies due to reduced fouling, lowambient controls to 23° F., electronic modulating hot gas bypass forcapacity control, TEFC pumps and nonferrous water circuit construction,Free cooling and tempered circuit 3-way valves with controls, 100 micronside-stream filter on evaporator recirculation and insulation onreservoir and chilled water piping. The system is factory tested underpartial and full load conditions.

The hybrid cooling system is provided within a NEMA-4 electricalenclosure with rotary non-fused disconnect and outdoor duty wiring withFree cooling system controls, NFPA-70 and NFPA-79 electricalspecifications and UL508A certified control panel, PID control algorithmwith load shedding, Remote magnetic display panel 8×22 LCD display (canbe mounted in a window kit if desired), alarm history screen providescritical information for troubleshooting and a remote chiller enable andalarm indication.

Digital displays are provide for Set Temperature, Pump Dischargepressure, Refrigerant Suction pressure, Leaving temperature, ReservoirLevel, Refrigerant discharge pressure, entering temperature, processorflow and compressor run time. Alarm Faults and Warnings are provided forthe Water Circuit as follows: High Leaving Temp Fault, Low Water LevelWarning, Low Leaving Temp Fault, Low Water Level Fault, Sensor FailureFault, High Water Level Fault, Low Evaporator Flow Fault, Pump MotorOverload, Low Flow Warning and Low Flow Fault. Alarm Faults and Warningsare provided for the Refrigeration Circuit as follows: Suction PressureWarning, Suction Pressure Fault, Discharge Pressure Warning, DischargePressure Fault and Compressor Motor Overload.

In a particular illustrative embodiment, galvanized steel structuralmembers are provided with heavy gauge aluminum cabinet panels,Corrugated aluminum fins with staggered copper tubes for optimum heattransfer, PVC-coated steel fan guards for optimum corrosion protection,Fully baffled fan sections to prevent reverse rotation, Aluminum fanblades statically and dynamically balanced, Energy efficient fan motorswith direct-drive fans, Weatherproof electrical enclosure withsingle-point field wiring and a UL listed control panel.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the present invention, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

The present invention contemplates a machine readable medium containinginstructions, or that which receives and executes instructions from apropagated signal so that a device connected to a network environmentcan send or receive voice, video or data, and to communicate over thenetwork using the instructions. The instructions may further betransmitted or received over a network via the network interface device.The machine readable medium may also contain a data structure forcontaining data useful in providing a functional relationship betweenthe data and a machine or computer in an illustrative embodiment of thedisclosed system and method.

While the machine-readable medium is shown in an example embodiment tobe a single medium, the term “machine-readable medium” should be takento include a single medium or multiple media (e.g., a centralized ordistributed database, and/or associated caches and servers) that storethe one or more sets of instructions. The term “machine-readable medium”shall also be taken to include any medium that is capable of storing,encoding or carrying a set of instructions for execution by the machineand that cause the machine to perform any one or more of themethodologies of the present invention. The term “machine-readablemedium” shall accordingly be taken to include, but not be limited to:solid-state memories such as a memory card or other package that housesone or more read-only (non-volatile) memories, random access memories,or other re-writable (volatile) memories; magneto-optical or opticalmedium such as a disk or tape; and/or a digital file attachment toe-mail or other self-contained information archive or set of archives isconsidered a distribution medium equivalent to a tangible storagemedium. Accordingly, the invention is considered to include any one ormore of a machine-readable medium or a distribution medium, as listedherein and including art-recognized equivalents and successor media, inwhich the software implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the invention is not limited to such standards andprotocols. Each of the standards represent examples of the state of theart. Such standards are periodically superseded by faster or moreefficient equivalents having essentially the same functions.Accordingly, replacement standards and protocols having the samefunctions are considered equivalents.

The illustrations of embodiments described herein are intended toprovide a general understanding of the structure of various embodiments,and they are not intended to serve as a complete description of all theelements and features of apparatus and systems that might make use ofthe structures described herein. Many other embodiments will be apparentto those of skill in the art upon reviewing the above description. Otherembodiments may be utilized and derived there from, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this disclosure. Figures are also merely representationaland may not be drawn to scale. Certain proportions thereof may beexaggerated, while others may be minimized Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments havebeen illustrated and described herein, it should be appreciated that anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separately claimed subject matter.

1. A hybrid cooling system, the system comprising: an array of solarcells electrically connected to inverters for producing electricity fromthe sun; a chiller controller processor in data communication with theinverters and a non-transitory computer readable medium; a chiller indata communication with the chiller controller processor and in thermalcommunication with inverters in a sealed enclosure, wherein theinverters are cooled by an inverter coolant fluid; an array of solarcells attached to the inverters for producing power from the sun; a freecooler in data communication with the chiller controller processor andin thermal communication with the inverter cooling fluid; and atemperature sensor apparatus in thermal communication with the invertercooling fluid; a switch for controlling an on off state for the chillerand the cooler, where in the processor for turns the chiller on and thecooler off when the inverter cooling fluid is above a predeterminedtemperature.
 2. The system of claim 1, further comprising a computerprogram in the non-transitory computer readable medium, the computerprogram comprising: instructions to control a fan speed for the chillerto use substantially a least amount to power to produce energy from thesun.
 3. The system of claim 1, further comprising a computer program inthe non-transitory computer readable medium, the computer programcomprising: instructions to current limit the inverters to a net energyproduction level.
 4. The system of claim 1, further comprising acomputer program in the non-transitory computer readable medium, thecomputer program comprising: instructions to stage in the inverters oneat a time to achieve a net energy production level.
 5. The system ofclaim 1, further comprising a computer program in the non-transitorycomputer readable medium, the computer program comprising: instructionsto stage the inverters for a given net energy production from the solararray.
 6. The system of claim 1, further comprising a computer programin the non-transitory computer readable medium, the computer programcomprising: instructions to control coolant temperature for theinverters by controlling a speed for fans on the free cooler.
 7. Thesystem of claim 1, further comprising a computer program in thenon-transitory computer readable medium, the computer programcomprising: instructions to control coolant temperature for theinverters by controlling a speed for fans on the chiller.
 8. The systemof claim 1, further comprising a computer program in the non-transitorycomputer readable medium, the computer program comprising: instructionsto de-rate the inverters to a reduced level of energy production when acoolant temperature exceeds a maximum level.
 9. The system of claim 1,further comprising a computer program in the non-transitory computerreadable medium, the computer program comprising: instructions tocontrol coolant temperature for the inverters by modulating exhaust gasfrom the compressor to heat the fluid to avoid condensation of water inair inside the sealed enclosure onto the inverters.
 10. The system ofclaim 1, further comprising a computer program in the non-transitorycomputer readable medium, the computer program comprising: a neutralnetwork for automatically controlling the system for substantiallymaximum energy production for a current ambient temperature and solararray energy supplied to the inverters.
 11. A method for controlling ahybrid cooling system for substantially net maximum energy production,the method comprising: monitoring at a chiller processor controller,energy output from an array of solar cells electrically connected toinverters for producing electricity from the sun; controlling at thechillier controller processor, a chiller in data communication with thechiller controller processor and in thermal communication with invertersin a sealed enclosure, wherein the inverters are cooled by an invertercoolant fluid, for net maximum energy production from an array of solarcells attached to the inverters for producing power from the sun;controlling at the chiller controller processor, a free cooler in datacommunication with the chiller controller processor and in thermalcommunication with the inverter cooling fluid; and monitoring at thechiller controller processor a temperature sensor apparatus in thermalcommunication with the inverter cooling fluid; and controlling at thechiller controller processor, a switch for controlling an on off statefor the chiller and the cooler, where in the processor for turns thechiller on and the cooler off when the inverter cooling fluid is above apredetermined temperature.
 12. The method of claim 11, furthercomprising control at the chiller controller processor, a fan speed forthe chiller to use substantially a least amount to power to produceenergy from the sun.
 13. The method of claim 11, further comprisingcurrent limiting at the chiller controller processor the inverters to asubstantially maximum net energy production level.
 14. The method ofclaim 11, further compressors, staging a the chiller controllerprocessors the inverters one at a time to achieve a net energyproduction level.
 15. The method of claim 11, further comprising stagingat the chiller controller processor, the inverters for a given netenergy production from the solar array.
 16. The method of claim 11, themethod further comprising, controlling at the chiller controllerprocessor, a coolant temperature for the inverters by controlling aspeed for fans on the free cooler.
 17. The method of claim 11, themethod further comprising, control coolant temperature for the invertersby controlling at the chiller controller processor a speed for fans onthe chiller.
 18. The method of claim 11, the method further comprising,de-rating at the chiller controller processor, the inverters to areduced level of energy production when a coolant temperature exceeds amaximum level.
 19. The method of claim 11, the method furthercomprising, controlling at the chiller controller processor, a coolanttemperature for the inverters by modulating exhaust gas from thecompressor to heat the fluid to avoid condensation of water in airinside the sealed enclosure onto the inverters.
 20. The method of claim11, the method further comprising, using a neutral network at thechiller controller process for automatically controlling the system forsubstantially maximum energy production for a current ambienttemperature and solar array energy supplied to the inverters.